Publications by authors named "Juan P Solano"

8 Publications

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Deep brain stimulation of midbrain locomotor circuits in the freely moving pig.

Brain Stimul 2021 Feb 27;14(3):467-476. Epub 2021 Feb 27.

Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, USA; The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA. Electronic address:

Background: Deep brain stimulation (DBS) of the mesencephalic locomotor region (MLR) has been studied as a therapeutic target in rodent models of stroke, parkinsonism, and spinal cord injury. Clinical DBS trials have targeted the closely related pedunculopontine nucleus in patients with Parkinson's disease as a therapy for gait dysfunction, with mixed reported outcomes. Recent studies suggest that optimizing the MLR target could improve its effectiveness.

Objective: We sought to determine if stereotaxic targeting and DBS in the midbrain of the pig, in a region anatomically similar to that previously identified as the MLR in other species, could initiate and modulate ongoing locomotion, as a step towards generating a large animal neuromodulation model of gait.

Methods: We implanted Medtronic 3389 electrodes into putative MLR structures in Yucatan micropigs to characterize the locomotor effects of acute DBS in this region, using EMG recordings, joint kinematics, and speed measurements on a manual treadmill.

Results: MLR DBS initiated and augmented locomotion in freely moving micropigs. Effective locomotor sites centered around the cuneiform nucleus and stimulation frequency controlled locomotor speed and stepping frequency. Off-target stimulation evoked defensive and aversive behaviors that precluded locomotion in the animals.

Conclusion: Pigs appear to have an MLR and can be used to model neuromodulation of this gait-promoting center. These results indicate that the pig is a useful model to guide future clinical studies for optimizing MLR DBS in cases of gait deficiencies associated with such conditions as Parkinson's disease, spinal cord injury, or stroke.
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http://dx.doi.org/10.1016/j.brs.2021.02.017DOI Listing
February 2021

Population Averaged Stereotaxic T2w MRI Brain Template for the Adult Yucatan Micropig.

Front Neuroanat 2020 13;14:599701. Epub 2020 Nov 13.

Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, United States.

Population averaged brain templates are an essential tool for imaging-based neuroscience research, providing investigators with information about the expected size and morphology of brain structures and the spatial relationships between them, within a demographic cross-section. This allows for a standardized comparison of neuroimaging data between subjects and provides neuroimaging software with a probabilistic framework upon which further processing and analysis can be based. Many different templates have been created to represent specific study populations and made publicly available for human and animal research. An increasingly studied animal model in the neurosciences that still lacks appropriate brain templates is the adult Yucatan micropig. In particular, T2-weighted templates are absent in this species as a whole. To address this need and provide a tool for neuroscientists wishing to pursue neuroimaging research in the adult micropig, we present the construction of population averaged ( = 16) T2-weighted MRI brain template for the adult Yucatan micropig. Additionally, we present initial analysis of T1-weighted ( = 3), and diffusion-weighted ( = 3) images through multimodal registration of these contrasts to our T2 template. The strategies used here may also be generalized to create similar templates for other study populations or species in need of template construction.
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http://dx.doi.org/10.3389/fnana.2020.599701DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7691581PMC
November 2020

Dichotomous Locomotor Recoveries Are Predicted by Acute Changes in Segmental Blood Flow after Thoracic Spinal Contusion Injuries in Pigs.

J Neurotrauma 2019 05 20;36(9):1399-1415. Epub 2018 Nov 20.

1 The Miami Project to Cure Paralysis, University of Miami, Miller School of Medicine, Miami, Florida.

Neuroimaging facilitates the translation of animal pre-clinical research to human application. The large porcine spinal cord is useful for testing invasive interventions. Ideally, the safety and efficacy of a delayed intervention is tested in pigs that have recovered sufficiently after spinal cord injury (SCI) to allow either deterioration or improvement of function to be detected. We set out to create moderate severity T9 injuries in Yucatan minipigs by conducting a bridging study adapting methods previously developed in infant piglets. The injury severity was varied according to two pneumatic impactor parameters: the piston compression depth into tissue or the velocity. To stratify locomotor recovery, a 10-point scale used in prior piglet studies was redefined through longitudinal observations of spontaneous recovery. Using hindlimb body weight support to discriminate injury severity, we found that end-point recovery was strongly bimodal to either non-weight-bearing plegia with reciprocating leg movements (<5/10) or recovery of weight bearing that improved toward a ceiling effect (≥ 8/10). No intermediate recovery animals were observed at 2 months post-injury. The ability of intra-operative ultrasound and acute magnetic resonance imaging (MRI) to provide immediate predictive feedback regarding tissue and vascular changes following SCI was assessed. There was an inverse association between locomotor outcome and early gray matter hemorrhage on MRI and ultrasound. Epicenter blood flow following contusion predicted recovery or non-recovery of weight-bearing. The depth of the dorsal cerebrospinal fluid space, which varied between animals, influenced injury severity and confounded the results in this fixed-stroke paradigm.
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http://dx.doi.org/10.1089/neu.2018.6087DOI Listing
May 2019

Intraspinal Delivery of Schwann Cells for Spinal Cord Injury.

Methods Mol Biol 2018 ;1739:467-484

The Miami Project to Cure Paralysis, University of Miami, Miller School of Medicine, Miami, FL, USA.

Cell transplant-mediated tissue repair of the damaged spinal cord is being tested in several clinical trials. The current candidates are neural stem cells, stromal cells, and autologous Schwann cells (aSC). Due to their peripheral origin and limited penetration of astrocytic regions, aSC are transplanted intralesionally as compared to neural stem cells that are transplanted into intact spinal cord. Injections into either location can cause iatrogenic injury, and thus technical precision is important in the therapeutic risk-benefit equation. In this chapter, we discuss how we bridged from transplant studies in large animals to human application for two Phase 1 aSC transplant studies, one subacute and one chronic. Preclinical SC transplant studies conducted at the University of Miami in 2009-2012 in rodents, minipigs, and primates supported a successful Investigational New Drug (IND) submission for a Phase 1 trial in subacute complete spinal cord injury (SCI). Our studies optimized the safety and efficiency of intralesional cell delivery for subacute human SCI and led to the development of new simpler techniques for cell delivery into subjects with chronic SCI. Key parameters of delivery methodology include precision localization of the injury site, stereotaxic devices to control needle trajectory, method of entry into the spinal cord, spinal cord motion reduction, the volume and density of the cell suspension, rate of delivery, and control of shear stresses on cells.
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http://dx.doi.org/10.1007/978-1-4939-7649-2_31DOI Listing
January 2019

Predicted Unfavorable Neurologic Outcome Is Overestimated by the Marshall Computed Tomography Score, Corticosteroid Randomization After Significant Head Injury (CRASH), and International Mission for Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury (IMPACT) Models in Patients with Severe Traumatic Brain Injury Managed with Early Decompressive Craniectomy.

World Neurosurg 2017 May 20;101:554-558. Epub 2017 Feb 20.

Department of Neurosurgery, Neiva University Hospital, Neiva, Colombia.

Introduction: Traumatic brain injury (TBI) is of public health interest and produces significant mortality and disability in Colombia. Calculators and prognostic models have been developed to establish neurologic outcomes. We tested prognostic models (the Marshall computed tomography [CT] score, International Mission for Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury (IMPACT), and Corticosteroid Randomization After Significant Head Injury) for 14-day mortality, 6-month mortality, and 6-month outcome in patients with TBI at a university hospital in Colombia.

Methods: A 127-patient cohort with TBI was treated in a regional trauma center in Colombia over 2 years and bivariate and multivariate analyses were used. Discriminatory power of the models, their accuracy, and precision was assessed by both logistic regression and area under the receiver operating characteristic curve (AUC). Shapiro-Wilk, χ, and Wilcoxon test were used to compare real outcomes in the cohort against predicted outcomes.

Results: The group's median age was 33 years, and 84.25% were male. The injury severity score median was 25, and median Glasgow Coma Scale motor score was 3. Six-month mortality was 29.13%. Six-month unfavorable outcome was 37%. Mortality prediction by Marshall CT score was 52.8%, P = 0.104 (AUC 0.585; 95% confidence interval [CI] 0 0.489-0.681), the mortality prediction by CRASH prognosis calculator was 59.9%, P < 0.001 (AUC 0.706; 95% CI 0.590-0.821), and the unfavorable outcome prediction by IMPACT was 77%, P < 0.048 (AUC 0.670; 95% CI 0.575-0.763).

Conclusions: In a university hospital in Colombia, the Marshall CT score, IMPACT, and Corticosteroid Randomization After Significant Head Injury models overestimated the adverse neurologic outcome in patients with severe head trauma.
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http://dx.doi.org/10.1016/j.wneu.2017.02.051DOI Listing
May 2017

Characterization of Motor and Somatosensory Evoked Potentials in the Yucatan Micropig Using Transcranial and Epidural Stimulation.

J Neurotrauma 2017 09 28;34(18):2595-2608. Epub 2016 Nov 28.

1 The Miami Project to Cure Paralysis, University of Miami , Miller School of Medicine, Miami, Florida.

Yucatan micropigs have brain and spinal cord dimensions similar to humans and are useful for certain spinal cord injury (SCI) translational studies. Micropigs are readily trained in behavioral tasks, allowing consistent testing of locomotor loss and recovery. However, there has been little description of their motor and sensory pathway neurophysiology. We established methods to assess motor and sensory cortical evoked potentials in the anesthetized, uninjured state. We also evaluated epidurally evoked motor and sensory stimuli from the T6 and T9 levels, spanning the intended contusion injury epicenter. Response detection frequency, mean latency and amplitude values, and variability of evoked potentials were determined. Somatosensory evoked potentials were reliable and best detected during stimulation of peripheral nerve and epidural stimulation by referencing the lateral cortex to midline Fz. The most reliable hindlimb motor evoked potential (MEP) occurred in tibialis anterior. We found MEPs in forelimb muscles in response to thoracic epidural stimulation likely generated from propriospinal pathways. Cranially stimulated MEPs were easier to evoke in the upper limbs than in the hindlimbs. Autopsy studies revealed substantial variations in cortical morphology between animals. This electrophysiological study establishes that neurophysiological measures can be reliably obtained in micropigs in a time frame compatible with other experimental procedures, such as SCI and transplantation. It underscores the need to better understand the motor control pathways, including the corticospinal tract, to determine which therapeutics are suitable for testing in the pig model.
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http://dx.doi.org/10.1089/neu.2016.4511DOI Listing
September 2017

Pediatric spinal cord injury in infant piglets: description of a new large animal model and review of the literature.

J Spinal Cord Med 2010 ;33(1):43-57

Pediatric Critical Care (R-131), University of Miami School of Medicine, 1611 NW 12th Avenue, Miami, FL 33136, USA.

Objective: To develop a new, clinically relevant large animal model of pediatric spinal cord injury (SCI) and compare the clinical and experimental features of pediatric SCI.

Methods: Infant piglets (3-5 weeks old) underwent contusive SCI by controlled cortical impactor at T7. Severe complete SCI was induced in 6 piglets, defined as SCI with no spontaneous return of sensorimotor function. Eight piglets received incomplete SCI, which was followed by partial recovery. Somatosensory evoked potentials, magnetic resonance imaging, neurobehavioral function, and histopathology were measured during a 28-day survival period.

Results: Mean SCI volume (defined as volume of necrotic tissue) was larger after complete compared with incomplete SCI (387 +/- 29 vs 77 +/- 38 mm3, respectively, P < 0.001). No functional recovery occurred after complete SCI. After incomplete SCI, piglets initially had an absence of lower extremity sensorimotor function, urinary and stool retention, and little to no rectal tone. Sensory responses recovered first (1-2 days after injury), followed by spontaneous voiding, lower extremity motor responses, regular bowel movements, and repetitive flexion-extension of the lower extremities when crawling. No piglet recovered spontaneous walking, although 4 of 8 animals with incomplete injuries were able to bear weight by 28 days. In vivo magnetic resonance imaging was performed safely, yielded high-resolution images of tissue injury, and correlated closely with injury volume seen on histopathology, which included intramedullary hemorrhage, cellular inflammation, necrosis, and apoptosis.

Conclusion: Piglets performed well as a reproducible model of traumatic pediatric SCI in a large animal with chronic survival and utilizing multiple outcome measures, including evoked potentials, magnetic resonance imaging, functional outcome scores, and histopathology.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2853328PMC
http://dx.doi.org/10.1080/10790268.2010.11689673DOI Listing
May 2010

Successful treatment with bortezomib of a refractory humoral rejection of the intestine after multivisceral transplantation.

Clin Transpl 2009 :465-9

Department of Surgery, University of Miami School of Medicine, Miami, Florida, USA.

Graft rejection is a serious complication after intestinal and multivisceral transplantation. Classic anti-rejection strategies often focus on addressing the cellular component, however mounting evidence suggests that antibody mediated rejection may also play an important role in patient and graft survival. Bortezomib, a proteasome inhibitor used in the treatment of multiple myeloma, has been found to be useful in treating antibody mediated rejection in kidney transplant recipients. The following case illustrates how bortezomib was used to successfully reverse refractory rejection in a patient following multivisceral transplantation. While the rejection was able to be controlled, this patient's course was complicated by an aggressive viral infection after bortezomib therapy. Bortezomib may be a useful agent in the treatment of rejection after intestinal and multivisceral transplantation; however more data is needed to assess its impact on infectious complications in this complex group of patients.
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July 2010